1. Field of the Invention
The solidification of cosmetic powders to produce pressed powder compositions is representative of a growing trend in the cosmetic arts. This growth in pressed powder compositions can be ascribed to at least two advantages that result from such packaging. For one thing, a solidified powder is portable. The user is likewise advantaged in that it can be applied without the messiness associated with loose powder. Indeed, certain cosmetic pressed powders, e.g., eyeshadows, blushes and the like, are presently available as solidified powders. That is, finely divided loose powders are placed into gaudets, i.e. pans, and under high pressure are pressed into cakes.
Although pressed powders provide the above discussed advantages they possess one detrimental characteristic. That is, the powder constituents do not bind with each other to form a solid. Thus, a binder, usually in liquid form, is added to provide this missing binding property. The use of one or more binders, however, is detrimental to users of cosmetic compositions who have oily skin. In order to provide beauty enhancement users who have oily skin require cosmetics which reduce, rather than increase, the oil level of surface layers of the skin. Certainly, the use of a cosmetic composition laden with oily binder decreases, rather than increases, the product's beauty enhancement to a user having an oily or even normal skin.
Another detrimental property associated with cosmetic powder compositions, which are usually pressed powders, is that, by containing high concentrations of oily binder, they obviously do not contain water soluble but oil insoluble humectants and other like moisturizing agents. The inclusion of moisturizing agents in cosmetic products is highly desirable in that these agents provide a soft comfortable feel to the skin.
2. Background of the Prior Art
A particularly pertinent disclosure of a powder composition is embodied in U.S. Pat. No. 4,724,138 to Duffy et al. Duffy et al. describes a method for forming a pigmented cosmetic powdered powder product which comprises blending a powder phase composition, which includes a powdered pigment and calcium sulfate hemihydrate, with an aqueous phase comprising water and a surfactant at elevated temperature, i.e., about 60.degree. C. The product of this combination is poured into a mold and allowed to set. The product is removed from the mold and dried at very high temperature, in excess of 128.degree. C., to produce a solid employed primarily in cosmetic stick products.
This high heat treatment prevents the cosmetic product from having the "feel" deemed attractive to users. That is, the product is not soft due to the high curing temperature and the resultant driving off of many cosmetically acceptable humectants which evaporate at these high processing temperatures.
U.S. Pat. No. 4,624,273 to Carr, another relevant reference, discloses a cosmetic pigmented pencil. The pencil of the Carr patent comprises a core consisting of a water-set mixture of plaster of paris, mica or other laminar material and pigment or color. The cosmetic composition disposed in the pre-formed core may also include preservatives and bacteriostats.
As in Duffy et al., the Carr patent does not address the need in the art for a free standing solid possessing high payoff. Rather than producing a free standing powder product, Carr is limited to a cosmetic pencil.